Sdk: dartanalyzer not picking up extension-methods experiment defined in analysis options

[pq]

To reproduce.

mkdir ext_test
cd ext_test
stagehand console-full

Update analysis_options.yaml to:

analyzer:
  enable-experiment:
    - extension-methods

and ext_test.dart to:

extension Foo on Object {

}

run pub get. Then you can analyze.

[~/tmp/ext_test] $ dartanalyzer .
Analyzing ext_test...
  error • This requires the 'extension-methods' experiment to be enabled at lib/ext_test.dart:1:1 • experiment_not_enabled
  error • Undefined class 'extension' at lib/ext_test.dart:1:1 • undefined_class
  error • Undefined class 'on' at lib/ext_test.dart:1:15 • undefined_class
  error • Functions must have an explicit list of parameters at lib/ext_test.dart:1:18 • missing_function_parameters
4 errors found.

This should analyze clean.

[~/tmp/ext_test] $ dart --version
Dart VM version: 2.5.0-edge.89c4f94b602eebb7db71fcf86619a2ef8c8d8085 (Mon Aug 19 17:28:32 2019 +0000) on "macos_x64"

fyi @bwilkerson @stereotype441

[pq]

Setting the option on the command line works as expected:

[~/tmp/ext_test] $ dartanalyzer --enable-experiment extension-methods .
Analyzing ext_test...
No issues found!

[bwilkerson]

@keertip Ran into this today too. I don't understand why it works for me and not for others. (Keerti and I were using the list notation, but I suspect that won't matter.)

[pq]

Keerti and I were using the list notation

whoops. That was a mistake. I was using the list version too. (Updated above.)

I did a bit of tracking down and see where the options are getting ignored but fixing it may be destabilizing... Let's discuss tomorrow!

[keertip]

The options not getting picked up was due to the fact that it was a nested package, so the analysis options in the package were not picked up. Adding the options to the top level analysis_options.yaml got it working.

[pq]

@keertip: was this using dartanalyzer or server?

[pq]

For discussion, here's where it looks like a specified options file is being dropped on the floor:

https://github.com/dart-lang/sdk/blob/1e79aa6b7e75551708c4b5ffb97a47b81e9a71cd/pkg/analyzer_cli/lib/src/has_context_mixin.dart#L20-L27

(that is, specified like dartanalyzer --options analysis_options.yaml).

[pq]

Why in this case dartanalyzer . is not picking up options in the default location is another (likely unrelated) issue.

[pq]

fyi also @MichaelRFairhurst

[keertip]

I got it to work with both the server and command line, command line with dartanalyzer --enable-experiment=extension-methods . Did not check if command line analyzer could pick up the from the analysis options file.

[egorikem]

Same situation here after updating to Dart 2.8, all of my extension are broken and dartanalyzer --enable-experiment=extension-methods is not a valid command, aka command not found

[pq]

@egorikem: is your package nested below another analysis_options.yaml?

[MichaelRFairhurst]

@egorikem what analysis error(s) are you getting?

[benjamin421]

Also getting an error on extensions class after updating to Dart 2.8. No errors in flutter doctor, on the master channel for the flutter sdk.
This requires the 'extension-methods' experiment to be enabled. Try enabling this experiment by adding it to the command line when compiling and running.

[lukepighetti]

[✓] Flutter (Channel master, v1.13.8-pre.58, on Mac OS X 10.14.6 18G2022, locale en-US)
    • Flutter version 1.13.8-pre.58 at /Users/lukepighetti/development/flutter
    • Framework revision fabf4e3d0d (7 hours ago), 2020-01-08 15:28:02 -0800
    • Engine revision 46adf73d51
    • Dart version 2.8.0 (build 2.8.0-dev.0.0 c0ca187f26)

Can't use extension methods, get the error referenced in this issue.

[pq]

/fyi @stereotype441

[benthillerkus]

Me too, I downgraded to stable in order to use them

[Rameshv]

VSCode complains This requires the 'extension-methods' experiment to be enabled. Try enabling this experiment by adding it to the command line when compiling and running. even though extension-methods flag is enabled.

So when I run dartanalyzer --enable-experiment extension-methods . it showed

 hint • Extension methods weren't supported until version 2.6.0, but this code is required to be able to run on earlier versions. • lib/utils/extensions.dart:1:1 • sdk_version_extension_methods

It was fixed after I changed the sdk enviorment to

environment:
  sdk: ">=2.6.0 <3.0.0"

[baddri]

It was fixed after I changed the sdk enviorment to

environment:
  sdk: ">=2.6.0 <3.0.0"

this work for me

[pq]

@lukepighetti @Rameshv (and all), do you see a diagnostic (and quick fix) like this when you hover over the error in the IDE?:

[lukepighetti]

Nope, but this seems to have resolved itself when I switched to dev channel

[DanTup]

@pq I had this raised at https://github.com/Dart-Code/Dart-Code/issues/2253 and I saw it too. It just gave the "Try enabling this experiment by adding it to the command line when compiling and running" message.

However I updated the SDK constraint to fix it, and then when I changed it back (and ran pub get and then restarted VS Code), I got the new message that posted. I can't figure out why I wasn't getting that before (nor get back to a state where I get that message!).

[pq]

/fyi @stereotype441 @bwilkerson

[bwilkerson]

Given that the extension methods experiment has now shipped as a full feature, I'm guessing this is no longer a problem.